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46 lines
1.5 KiB
C++
46 lines
1.5 KiB
C++
// Copyright 2023 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef THIRD_PARTY_NEARBY_INTERNAL_WEAVE_PACKET_SEQUENCE_NUMBER_GENERATOR_H_
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#define THIRD_PARTY_NEARBY_INTERNAL_WEAVE_PACKET_SEQUENCE_NUMBER_GENERATOR_H_
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#include "absl/base/thread_annotations.h"
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#include "internal/platform/mutex.h"
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namespace nearby {
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namespace weave {
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// Keeps a counter of the next Weave packet to set the new Weave packet sequence
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// number in a connection. This counter automatically rolls over once it hits 7,
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// since 3 bits are allocated in the packet to the counter, making its max value
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// 0b111, or 7.
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class PacketSequenceNumberGenerator {
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public:
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// Returns the next counter in the sequence, incrementing the counter
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// internally.
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int Next();
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// Resets the counter to 0.
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void Reset();
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private:
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Mutex mutex_;
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int packet_counter_ ABSL_GUARDED_BY(mutex_) = 0;
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};
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} // namespace weave
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} // namespace nearby
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#endif // THIRD_PARTY_NEARBY_INTERNAL_WEAVE_PACKET_SEQUENCE_NUMBER_GENERATOR_H_
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